Magneto



' S of the rotor extending from the Patented May 22, 19233.

UNITED STATES PATENT OFFICE.

BUTLER AMES, E LOYJ'ELL, IviASSACE-IIJSETTS.

Application filed February 16, 1919.

To all 107mm may concern Be it known that I, BUTLER AMI-is, a citi zenof the United States, and resident of Lowell, in the county orl'diddlesex and State of Massachusetts, have invented new and usefulImprovements in lilagnetiics, (it which the following is 2v secitication.

This invention relates to magnetoes and more particularly to theconstruction of the rotor and circuit nia-lre-ainl-breal-z mechanism andto the means for securing the rotating together. The objects of theinvention are to provide improved meets for mountingcircuitInalre-and-brealr mechanism on the rotor of the magneto, toprovide in'iproved means for mounting a condense: on the rotor of themagneto, 1rd to provide improved make-and-breal mechanism tor a magneto.

In the accompanyin illustrate the preterret invention,-

Figure l is a side neto, parts being broken away interior mechanism insection;

Figure 2 is an end elovatioi'i of the magneto viewed from the right-handend of 1, the-end rover oi the casing being open; and

drawinns l embodiment oi my 1 e 1 C V i eleuition O}. the mag;

to sh ow th e Figure 3 is a perspective view of an improved lug forminga part of the circuit makeand-break mechanism.

The preferred embodiment of my invention illustrated in the drawingscomprises, in general, a casing C, a rotor R ournaled in the oppositeends of the casing, the shaft left-hand end of the casing as shown inFig. 1,, rality 0i U-magnets M for prouuci" magnetic field, and a lead L"for cor .ucting current from the rotor. The right-hand end E of thecasing C is detachably secured to the casing by means of bolts 1 topermit the insertion of the rotor into the casing. The end E of thecasing is provided with an outwardly extending hub 2 upon which ismounted a housing H for the circuit makeand-break mechanism. The housingH is closed at its outer end by means of a cap 3 which is hinged to thehousing at A spring arm 5 is pivotally mounted on the outer end of a lug6 extending outwardly from the end F of the casin for the pnrgpiose ofholding the cap 3 in closed position. The arm 5 normally occupies theposition shown Serial No.

the end plate 8 has a hollow hub 10 ex- 1 Sci to .ding outwardlytherefrom concentricallv til u the axis of the rotor and around theinner end of this hub s provided a roller bearing 11 for Ollllltlilllg'the right-hand end oi the rotor in the end B of the casing (I. The hub10 extends outwardly beyond the roller bearing 11 and upon the outer endor the hub is mounted the circuit make-and l oreali IDQI'llZUllSlllwhich will now be described.

The circuit 1 aire-and-break mechanism n comprises disk 12 disposedtransversely of the axis of the rotor and. provided with a hollow hub 13adapted to [it over the rotor hub 10, the two hubs being tapered so asto fit tightly together. The rotor hub 13 is provided on the outerperiphery of its tapered end portion with a lrey way adapted to receivean indentation 1-1 struck up from the hollow hub 13 of the disk 12. Onthe outer face of the disk 12 in the central axial region of the disk isdisposed a lug 15. L he lug has three arms 16, 1'7 and 18 arranged inthe form of a "i" for securing the lug to the dish These arms aresecured to the disk by means of rivets or screws 19 and 1C insulatedfrom the disk by means of a layer of in ,ilation 20 and from the rivetsor screws by means of washers and bushing. The lug 15 has a lateral armin which is mounted switch contact 23, the contact 23 being threadedthrough the arm 22 so that may be longitudinally adjusted. The switchcontact an cooperating with the switch contact 23 is mounted on the endof a bellcranl; 25, the bell cranlr being pivotally mounted on lugextending outwardly from the disk 12. The other end of. the bell-crank25 is provided with a cam member adapted to engage cams 28, which aresecured to the inner tare oil the housing H by means oi screws $8, tomove the switch inen'iber out of contact with the switch member 23, thebell-crank being urged in a clockwise direction to close the switchcontacts by means of a spring 2% mounted at one end on the dish 12 bymeans ot a lug 2'30 and being attached at the other end to thebell-crank by means of a screw 31. swing arm 32 is pivotally mounted onthe outer end of a lug 33 extending outwardly from the disk 12 betweenthe arms 16 and 17 so as to swing alout the axis of the lug 33 into andout of the position shown in Fig. 2. The tree end (it the spring arm 82is iupped outwardly at 3 1; to rccci re the outward end 01 the lug uponwhich the beltcrank is rotatably mounted so that when the spring arm isin the position shown in li 2 its outer end bears do\vnwardly on thebell-crank in the region of. i'ts'pivot to hold the bell-crank on thepivot, the cup 34 being adapted to receive the projecting end of thebell-crank pivot. The lug 33 is made hollow and within the hollow of thelug is provided a current conducting brush 35 and a compression spring36 to urge "the brush 35 against the tare 37 ot' the end memberl3, thebrush 35 serving toground the rotating disk 12 on the casing.

\Vithin the recess 7 in the end of the rotor is disposed an electricalcondenser 38 5111111- lar to the one described in my aforesaidapplication. The condenser has two end plates and 51 respectivelyconnected to alternate layers of the metallic foil or other conductingsheets comprising the body oi the condenser. A ground plate 52 1sseparated from the end plate 51 by a layerot' insulating material theplate having a central opening 54 therethrough. The plates 50, 51 and 52are held tightly together by rivets 55 at the four corners of thecondenser, the rivets contacting with plates 50 and 52 but beinginsulated from plate 51. The plate 52 is secured to end 8 of the rotorby screws. The end plates 50 and 51 are connected in bridge of theprimary winding of the rotor (not shown) by means of binding posts 57and 58. the plate 50 being grounded through the rivets 55 and plate 52and the plate 51 not being grounded.

Projecting outwardly from the center of plate 51 through the opening 5%in plate 52 is an internally threaded tube 39. A machine screw 40extends through an axial opening 41 in the lug 15 and threads into thetubular projection 39 on the condenser thereby clamping the condenserand the circuit make-and-break mechanism to the end plate A of therotor. the condenser 38 being drawn against the inner face of the end Sand the circuit make-and-break mechanism being drawn on to the outer endof the hub 10. A sleeve 43 of suitable insulating material is insertedbetween the tubular projection 39 and the hollow hub 10. A steel spring44 is secured to one side of the housing H so as to extend over the endof the screw 40 and bear inwardly thereon through the medium ot a brassbearing disk 45. A portion of the spring at is broken away in Fig. 2 andthe position of the broken portion is indicated in dot and dash lines.The spring as. is insulated from the housing H by a layer o't insulation16 and is connected to a binding post 21, the spring affording means forshort-circuiting the make-andbreak mechanism when it is desired torender the magnets inoperative.

The operation of my improved magneto is substantially the same as thatof certain well known types and need not be described in detail. Sutliceit to say that the makeand-break mechanism and condenser are rigidlysecured to the end of the rotor so as to rotate therewith. The switchmembers 23 and 2-1- are normally closed and are opened by means of arms28 four times during each revolution of the rotor, although it will ofcourse be understood that the cams may be arranged to open the switchmembers two or six or any desired number of times per revolutiondepending upon the number of poles on the rotor, etc. lt will heundm'stoml that the switch contacts 23 and 24 are connected in thecircuit of the primary coil of the magneto for the purpose of normallyshort-circuiting the primary, and that the condenser 38 is connected inparallel with the switch contacts. The ungrounded side of the primaryand condenser are connected to ground over the following circuit:Condenser plate 51, tubular projection 39, screw 41, lug 15, switchcontact 23. switch contact 24, bell-crank 25, spring 29, lug 30, disk12, lug 33, brush 35, and thence to the casing E which is grounded.

()ne of the cardinal features of the present invention resides in themeans for mounting the make-and-break mechanism on the rotor. Bytelescoping the hub 3 over the hub 10 the engaging surfaces between thetwo hubs are disposed at a greater radial distance from the axis of therotor than it the hub 12-3 were made sutficiently small to telescopeinto the hub 10. Thus the tendency for the make-and-break mechanism torotate on the hub is greatly reduced, and a circumferential displacementof the keyway or indentation from the proper point in forming same willproduce a smaller error in. the timing of the mechanism. Moreover bymaking the hub 13 fit over instead of into the hub 10 the keywa on thehub may be more easily cut inasmuch as it is disposed in the outerinstead of the inner periphery of the hub 10. By striking up theindentation 14 which is adapted to cooperate with the keyway in hub 10the key connection can be made more easily and cheaply and the largerdiameter of the hub 1 1 resulting from its fitting over instead of intothe hub 10 facilitates the formation of indentation 1 1.

Another cardinal feature of the invention comprises the lug 15 havingthe radially projecting arms 16, 17 and 18. By virtue of thisconstruction the lug may be rigidly secured to the disk 12 near theouter periphcry of the disk. If the collar 13 tends to rotate on collar10 the connection between the condenser and the lug 15 comprising thescrew 41 would tend to rotate the disk through the medium of lug 15thereby producing a torsional stress in the connection between the lugand the disk. By providing this connection comprising rivets 19 at aconsiderable radial distance from the axis of the rotor there is muchless danger of the connection being broken by this stress. The forkedarms 16 and 17 straddle the lug thereby producing a symmetricalconstruction resulting in greater compartness and rigidity. lVith thelug 15 secured to the disk 12 in the aforesaid manner it is praeticallyintegral with the disk and the opening for contact screw 28 may bedrilled after the lug is secured to the disk and while the device ismounted in the employed in drilling the opening in the disk for lug 1"?I claim:

1. A magneto comprising a rotor, a pair of switch members, a disksecured to the end of the rotor transversely of the axis of the rotorfor supporting one of said switch members, and a lug disposed in thecentral region of said disk for supporting the other of said switchmembers, said lug having a plurality of arms extending outwardly indivergent directions for securing the lug to said disk.

2. A magneto comprising a rotor, a pair of switch members, a disksecured to the end of the rotor transversely of the axis of the rotorfor supporting one of said switch members, and a lug disposed in thecentral region of said disk for supporting the other of said switchmembers, said lug having a plurality of arms extendingoutwardly in theform of a i for securing the lug to Said disk.

3. A magneto comprising a rotor, a pair of switch members, a disksecured to the end of the rotor transversely of tie axis of the rotorfor supporting one of said switch members, and a lug disposed in thecentral region of said disk for supporting the other of said switchmembers, a second lug for holding said first switch member on said disk,said second lug being mounted on said disk at one side of said firstlug, said first lug having a pair of arms straddling said second lug forsecuring the first lug to said disk.

Signed by me at Boston, Mass, this 23rd day of January 1919.

BUTLEP AMES.

